| CPC H04N 19/12 (2014.11) [H04N 19/124 (2014.11); H04N 19/18 (2014.11); H04N 19/625 (2014.11); H04N 19/619 (2014.11)] | 2 Claims |
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1. An encoder that encodes a first current block and a second current block in a picture, the encoder comprising:
circuitry; and
memory, wherein
using the memory, the circuitry:
when an intra prediction is used for the first current block and the second current block,
performs a first transform on (i) a first residual signal of the first current block using a first transform basis and (ii) a second residual signal of the second current block using a second transform basis, to generate first transform coefficients;
performs a second transform on the first transform coefficients of the first current block using a third transform basis to generate second transform coefficients and quantizes the second transform coefficients, when the first transform basis used for the first transform on the first residual signal is same as a predetermined transform basis; and
quantizes the first transform coefficients of the second current block without performing the second transform, when the second transform basis used for the first transform on the second residual signal is different from the predetermined transform basis, and
when an inter prediction is used for the first current block and the second current block,
performs the first transform on the first residual signal and the second residual signal using a fourth transform basis to generate third transform coefficients and quantizes the third transform coefficients without performing the second transform regardless of whether or not the fourth transform basis is same as the predetermined transform basis.
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